1. Field of the Invention
The invention relates to a combined jet engine having a ramjet and a turbojet and more specifically relates to a mechanism for conveniently passing between the two different operating modes.
2. Discussion of the Background
Turbojet propulsion is currently used in aircraft in supersonic flight up to roughly four times the speed of sound (Mach 4), but the ramjet is used for obtaining even higher speeds (Mach 7 or 8).
As the air is at a very high temperature during the use of the ramjet, it cannot pass through the turbine of the turbojet and must therefore skirt the stream where said turbine is located and passes through the ramjet channels.
Frequently discharge channels are added which skirt the turbine and the ramjet burners and which in part divert the air, which only mixes again with the remainder of the air at the jet engine discharge pipe in order to improve the flow lift and efficiency of the jet engine. These discharge channels, used exclusively in the turbojet mode, make the transition process from one operating mode to the other more difficult and the prior art flap systems, which open or close roughly simultaneously in order to bring about the desired operation are not entirely satisfactory and are frequently responsible for a thrust loss of the jet engine during switching processes.